Drying kiln



April 15, 1930. J F, COBB 1,754,351

DRYING KILN Filled July 21, 1924 4 Sheets-Sheet l Stigan Q "n o gsm :Em l- G E9 e A m Q o H* k) v l 1 1 k -O .rl 5 Q U N o N o A y) y t L3 Ev lq 31a/venten JfF. COBB vDMING KILN April 15, 1930.

Filed July 21, 1924: 4 sheets-smet 5 J F. COBB DRYING KILN April 15, 1930.

Filed July 21, 1924 4 Sheets-Sheet 4 GGOOOOOO\0OOO OOOOOOOGMVOOQU OOOOOGAFOOOO MMQQ gnou/Hoz;

Patented Apr. l5, 1930 UNITED STATES PATENToFFlcE J' IORREST COBB,!OF PORTLAND, OREGON, ASSIGNOR TO MOORE DRY KILN' COMPANY, A i CORPORATION OF FLORIDA DRYING KILN Application filed J'uly 21,

, My invention relates toimprovements-in kilns for drying diterent substances, 'but particularly lumber, by the application of a circulatory gaseous drying medium, either with or without use of artificial heat.`

One object of my invention is to produce a kiln which is operative atl all times, and exclusively if desired, by'means of a gaseous drying medium circulated in the kiln simply upon the application thereto of heat derived from heating pipes disposed preferably in the lower part of the kiln, with provision of special` means for eecting upward movement y through y ing medium from said pipes and back? again thereto in constant circulation.

Another object of my invention is to produce circulation of thedrying medium through the employment of a fan operatively communicating with the medium of circula-` tion withinthe kiln. Said fan may be used to effect circulation either independently of or in conjunction with and as an auxiliary to the means of circulation described in the last preceding paragraph. I prefer, in emto locate it upon the outside of the kiln,l and Imake the kiln operative as by means of `heat-compelled circulaloying such a fan,

.tion without interfering in any way withl `the operation of the kiln independently of the fan,

the kiln may exclusion of any other means of operating it',

if it be desired so to operate it. Also as well as by heat-promoted circulation withv out the aid ofthe fan.

' Other objects of my invention will be ap- 'I parent from the following specification in .which what constitutes my invention is first described in detail. and then succinctly' de- A 1,0 fined in the appended claim.

` Referring to they accompanying drawings,

' Figure I is a transverse vertical section of y a kiln constituting'one form of embodiment 'of my invention. I

modifiedlform' of embodiment.

s Figure III'is a longitudinal vertical section as on the line III-III of Figure I, and extending the full length of the kiln,

` Figure IV is a detached perspectlve view the interior of the kiln of the dry-` be operated by the fan to the'l 4Figure II isa similar view ofna kiln in a' 1924. Serial No. 727,305.

of a fan and its duets in present preferred form of embodiment of my invention as applied tothe kiln shown in Figure I.

Figure V is a view similar to Figure IV showing a modified arrangement of such a fan and its ducts as is applicable to the form of kiln shown in Figure II. r

Figure VI is a view similar to Figure I showing a fan-operated kiln of the type shown in Figure I. y v

Figure VII is a view corresponding to Figure but illustrative of a similar modication as applied to the subject-matter of Figure II.

Referring to the numerals on the drawings, l indicatesanadequately tire-.proof wall that is closed on all sides so as to form a kiln, and which may be made of any suitable and preferred design, material, and dimensions. The wall is penetrated, preferably at the opposite ends of the kiln, by the usual doors13 constructed in` any manner, either such as is usual in the art or as may be suitable and adapted for the purpose.

A construction of kiln that is well adapted lfor my purpose is one made in whole or in,- part Vof concrete, and that construction may vbe regarded as the one illustrated in the drawings. A

y At any desired and convenient height above the floor 2 of the kiln, I prefer to provide a succession of horizontal cross-beams 3, of such number, weight, dimensions, and distribution, as the size and capacity, of the kiln may require.- The cross-beams 3 are exg5 amples only of 'any suitable means of support for the-material to be dried. Tothat end I prefer to provide upon them paralleltr'ack rails 4 and 5, extending through the kiln from endto end, and adaptedfor the'gy support and operative accommodation of Y represented by a stack 8 of lumber piled edgewise, with spaces 9 between the boards wide enough for the proper circulation through them of a gaseous drying medium. Suitable means for confining the load upon the car platform are of course contemplated, and are represented in Figure I by side stakes 10 united at their tops by tie-stays 11, for example.

In Figure II, I illustrate a load 12 of boards piled sidewise upon the car platform 7, with orizontal spaces 14 between the boards for the circulation through them vof the drying medium, and built so as to define, for instance, a capped medial chimney 15 extending, in effect, the full length of the kiln-charge, and formed in a manner wellknown in the art by one method commonlyemployed in the piling of lumber. l f

The illustration of the two modifications of vmy invention shown by way of example 1n Figures I and II, is offered Afor the purpose of clearly indicating a breadth of scope of my invention intended.

In F1gure I, I show two baille-plates 16 and 17 .located towards opposite sides of the kiln and comprising divergent sections 18 and 19, respectively, Joined t ereto along their upper edges, and in turn surmounted, respect1vely, by substantially vertical plates 20 and 21. The bathe-plates 1n any form of embodiment extend the full length of the kiln substantially, Aso as to constitute in effect division walls for effecting operative circulation `of the drying medium within the kiln. The several parts of each baille-plate constitute, in

effect, one member. They are preferably combined in one integral structure, in all instances, and may likewise be made of metal, concrete, or any suitable material.

The plates 2O and 21 if employed, as they preferably are, or otherwise the `upper edges of the members 18 and 19 of the baile-plates, extend substantially the full width of the platform 7, so as to deiine a flue extending the full length of the kiln below the track vrails 4 and 5 for properly directing movement of the circulatory drying medium, ample spaces for the circulation of the drying medium being provided between the lower edges`23 of the bathe-plates 16 and 17 and the floor 2 of the kiln.

Within the space defined between the x lengths of the baiile-plates 16 and 17 and the opposite side walls ofthe kiln, respectively, I provide, in such a device as is shown in Figure I, two systems or coils of heating pipes 24 and 25, which may be madeof preferred arrangement of pipe sections in cooperative assemblage and spaced apart for passage between them of the gaseous circulatory medium. The respective coils 24 and 25 make operative communication'with any ordinary source of heat located outside the kkiln, and unnecessary to illustrate. The

pipes of the respective heating coils may be carried on cross-supports 27 sustained by pipe-hangers 28, but this is only an example of referred structural details. y bove each of the coils 24 and 25, respectively, I prefer to provide an accelerator pipe 3() which extends substantially the entire interior length of the kiln, and which is provided along its length with a row of upwardly discharging orifices through which a blast of heated air or a spray of steam may be discharged with the effect of accelerating, or of both accelerating and humidifying the passing circulatory medium. A corresponding, downwardly discharging, .accelerator pipe 31 may be used to advantage between the baille-plates 16 and 17, where it vmay be conveniently carried, for instance, upon the topmost row 'of cross-supports 27. I also prefer to provide along the top of the kiln, at required intervals, ventilators 32, which may be of any suitable form preferred.

The description of the heating apparatus `above specified is that shown in Figuresk I and III. of the drawings, and is adapted to provide within the kiln a downward circulation of air through the material to be dried that is loaded upon the cross-bars of the car platform 7. In that case separate currents of the circulatory medium pass upwardly alongthe opposite sides of the kiln, as shown by arrows in Figure I.

In Figure II, I show a heating means corresponding substantially in form and lfunction to that shown in Figure I, with this variation, that in Figure II, baffle-plates 35 and 36 are employed which flank a sin le heating coil 37 and partially cover it wit roof-like sections 38 and 39. The baille-plate sections 38 and 39 are separated between their 0E- posing horizontal edges 40 by a space su stantially equal in width tothat of the bottom of the longitudinally extended chimney 15. In Figure II, also, I show lateral downwardly .discharging accelerator pipes 41 and 42, and an upwardly discharging medial accelerator pipe 43, said pipes corresponding in function to the accelerator pipes 30 and 31 already specified. Accelerator pipes of the type just indicated may be multiplied in number, if desired, and located wherever they may be disposed to advantage.

The difference in the heating system shown and described with respect to Figure I and that shown and described with respect to Figure II is this, that while the heating coils of both systems establish an upward movement of the gaseous heating'medium through them, the location of the two heating coils u on the outside of the baille-plates 16 and 17) effects an upward movementof the circulatory medium along the sides of the kiln and a downward movement thereof through the body of the material tobe dried, whereas, in Figure II the movement of said mediumA directed from the single coil 37 causes circulation of the circulatory medium vertically and.

laterally through the chimney v15, and then downwardly along the opposite sides of the kiln. The result in each instance is substantially identical in respect to. the drying operation, the one system lending itself most advantageously to the edgewise method of lumber pilin and 'the other to the sidewise method o lumber piling.

Having described my kiln in respect .to its two methods-of heating the same, I come now to description of means contemplated for promoting circulation of the drying or heating medium within the kiln, either inv conjunction with or without heating appliances, through the employment.v of a fan `indicated,

fOreXample, in Figures IV and V, respectively. V ,The means illustrated in the former is applicablefto the form of kiln shown in Figure I, and that illustrated in the latter,

to that shown in Figure II. 4 In Figure I, I illustrate in cross-section, below the ioor 2 and between it and the bottom wall 45 of the kiln, three ducts separated as by partition walls 46 and 47. The medial duct 48 therein is the return duct, and the lateral ducts 49 and 50 are the delivery ducts. Each duct extends substantially the full length ofthe interior'of the kiln, and each is brought into operative communication, at one end,

with a fan-case 53 representative of a powerv In Figure IV the ducts driven fan or fans. 49 and 50 unite, as indicated at 51, so as to communicate, respectively, with the fan-discharge, and the du t 48 operatively communicates with the fanntake. In Figure IV, also, the ducts 48, 49, and 50, are shown as made, forv example, of metal and separable from the kiln upon the outside of which the fan-case 53 is preferablyv located. This construction is entirely practicable, but it should be understood that t e fan may be operatively connected directly with ducts formed in the material of the kiln itself instead of being made of lseparable metallic members 'insertable into the same. The ducts 48, .49, and 50, are preferably in effect constricted for pressure equalization purposes, preferably by being tapered,.towards their ends opposite the fan-case 53. Their ends next to said case should be of an area in cross-section substantially equal to theMfan-intake and discharge openings, respectively, -while their lopposite ends .may vary in area lof lcross-section according' to variable determining factors. Along the length of each duct is provided a series of apertures 54 equi ped with ordinary upwardly directing de ectors if desired,

2, inv case the Hoor and the duct employed are separate elements.

The construction shown inV Figure V is substantially the same as that shown and described in Figure IV, with the one exception that in the arrangement illustrated inFigure vV, it being applicable to the form of kiln yreturn duct shown in Figure IV.

The precise location of the delivery and return ducts, in any form of arrangement of them which may be employed, is not limited .to disposition underneath the floor 2. On

the contrary they may be disposed anywhere within the kiln where theymay functionate to advantage in substantially the same manner in which they functionate in their respective dispositions herein illustrated and described. Also, the returnV and delivery ducts, respectively, may be ralniiied to any .extent desired if itbe found advantageous to divide any or all of them into branches.

The modification shown in Figure VI simply consists of extension of the respective name-plates 16 and 17 of Figure I to the floor 2 of the kiln with the effect of closing the openings shown in Figure I between the lowerl edges 23 of said bathe-plates and the floor. The baffle-plates so extended, as shown in Figure VI, are distinctively indicated by reference numerals 6l and 62.

Figure VII shows the bafiie-plates 35 and 36 of Figure II downwardly extended in like manner and with similar elfectto what is shown inA Figure VI.. 'lhey extended baiiieplates in Figure VII are indicated for distinction by reference numerals 63 and 64, respectively. v

The operation of my invention may be, in view of the foregoing, described as follows. In respect to its embodiment shown in Figure I, the heating coils 24 and 25, when heated,

serve by rarefaction of the air within the `its accumulated gaseous additions constitut-U ing the circulatory heating medium, in the direction of the arrows shown in Figure I.` The means just described are suiiicient to effect the drying of the contents of the kiln, and, forsome urposes, that drying means is all suicient. f,- however, a more rapid drying eifect is desired, as occasion may demand, the fan 53 may be brought into requisition at any time as an auxiliary means of circulation. It should .be observed, however, that the kiln is at all times operable independently of the fan, and that the interruption of the operation of the fan, through accident,

operation, to descend artificial heat, maybe, by proper attention to humidification, relied upon to effect the drying operation desired. Under such conditons the fan becomes an element of prime im ortance in my invention.

ith respect to the kiln shown in Figure II, littledescription of operation in addition to what has been already specified isl necessary. Repeating that the heating coil 37 effects an upward movement of air through .the

chimney 15, thence laterally through the lumber pile 12, and thence downwardly along the sides of the kiln, as shown by the arrows, it is deemed sufficient to explain that in Figure I there are two heating coils^in stead of the one in Figure II. The substitution of two return ducts to the fan as shown in Figure II,for the one return duct as shown in Figure I, accomplishes Yin effect the same result for the single medially located coil 37 as thataccomplished in Figure I for the two heating coils 24 and 25, with reversal of the circulatory medium, even against theY tendency of movement imparted to it by the funtionating of the heating coils alone. The result so obtained may be, under varying conditions, distinctly advantageous whether the fan is used in conjunction with the heating coils or not. Therefore the potential reversibility of the. fan in combination with its cooperative elements is regarded as a feature of my invention of no minor importance.

What I claim is:

In a drying kiln, the combination with enclosure-deinmg walls, of means for causing continuous circulation of a gaseous drying medium within said enclosure, said means consisting of air delivery and return ducts, and fan mechanism in operative communication therewith, respectively, .said ducts consisting of metallic members separably insertv able into openings provided in said enclosure for their reception. l

In testimony whereof, I have hereunto set my hand.

J FORREST COBB.

only of the dlrection of circulation` of the Y heating medium.

In the modifications of my invention shown in Figures VI and lVII, respectively,

circulation may be effected by aid of the fan tive heating coils 24 and 25, or the single Y coil 37. It should be observed, however, that circulation. Besides the in such case the entire volume "f the drying medium is caused to ass through the fancase 53 in order to e ect complete circulation, while in the kilns shown in Fi res I either with or without the aid of the respecand II it is necessary to ,draw oft' t rough the fan-case only a portion of the entire volume of the drying medium in effecting its ortion of the drying medium drawn directlyT through the fancase, other ortions thereof will be, by. in-

duced circu ation, kept stirring and secure against stagnation anywhere within the kiln.

In the descri tion of my invention hitherto, the fan has en assumed to be operative so as to promote only currents of the circulating medium flowing in the same direction lwith such flow of thecirculatory medium as would be effected by-the resence and functioning of the' heating co' s aforesaid. It is important to note, however, that it is desirable, under some conditions, to reverse the direction of rotation of the fan, with the ref sult of reversing the direction of movement 

